Cryomech CPA289C, Installation And Operation Manual

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Overview
1-1
Section 1: Overview
This section provides a general overview of a cryocooler, the organizational structure of
this manual, and a glossary of defined terms and acronyms.
1.1 Cryocooler system
1.1.1 General description
The operation of a Cryomech cryocooler is based on a closed-loop helium expansion cycle.
The cryocooler consists of a helium compressor package, cold head, flex lines and cold
head motor cord.
The compressor package receives low pressure helium from the cold head, pressurizes
the helium gas and returns high pressure helium gas to the cold head via flex lines. The
cold head reaches cryogenic temperatures through adiabatic expansion by using the high
pressure helium gas from the helium compressor package and discharging low pressure
helium gas and returning it to the compressor package.
1.1.2 Organization of the manual
This manual is divided into eight section that provide the information needed to install,
operate and perform maintenance on a Cryomech cryocooler. It is important to note that
bulleted list may be performed in any order but numbered lists (labeled 1, 2, etc.) are
representative of sequential actions that must be performed in the order listed.
1.2 Glossary
1.2.1 Definitions
Aeroquip Couplings:
The term "Aeroquip couplings" is used generically to describe the self-sealing fittings that
connect components, e.g. helium flex lines are connected to the helium compressor
package and to the cold head via Aeroquip couplings.
Category II Installation:
Category II refers to the potential for transient over-voltage conditions in the mains power
connection to the equipment. See IEC 664, Sub-clause 5.6 for further details.
Closed Loop System:
This refers to a cryogenic system that has no helium loss.
Cold Head:
The cold head is an expansion device which is capable of reaching cryogenic
temperatures.
Cold Head Motor Cord:
The cold head motor cord provides electrical power from the helium compressor package
to the cold head motor.